Insulator



Oct. 30, 1928.

Will/[l INSULATOR """Filedmarcn 23. 1920 C. AALBORG INVENTOR Cbt/'Jima Aalbo/y ATTORNEY i WITNESSES; wma/wif l Patented Oct. '30, 1928.

UNITED sTATEs CHRISTIAN AALBORG, F PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC t MANUFACTURING COMPANY,I A CORPORATION OF VANIA.

PENNSYL- INSULATOR.

.Application led March 23, 1920. Serial No. 368,138.

vide an insulator and end members therefor that shall be s0 formed and related as to mechanically reinforce and protect the insulator and effectively distribute dielectric stresses therein.

In practicing my invention, I provide van insulating body member having openings at each end and end members each having an outer fiange embracing the insulating member and a central portion of substantially inverted cup-shape projecting into the insulating member for a relatively great distance.

l The arrangement so protects all of the inner and outer surfaces adjacent to the ends ofthe insulating member and so reinforces the latter as to greatly add to the mechanical strength of the device and so directs or distributes thedielectric stresses as to lessen the likelihood of damage to the insulator by these stresses. f l Figure 1 of the accompanying drawings is a longitudinal sectional view of an insulator constructed in accordance with my invention, and Fig. 2 is a similar view of a modified form thereof.

An insulating body member 1, preferably of porcelain, is provided, at its ends, with discoidal members 2 and 3 of relatively thin material,` preferably pressed from sheet metal, having flanges 4 and 5 embracing the outer edges of the member 1 and centrally disposed r 0 portions 6 and 7 of inverted substantially cupeshape projecting in the direction of the flanges 4 and 5, respectively, into openings in the ,ends of the body member 1. The portions 6 and 7 extend beyond the flanges 4 and 5, respectively, for a relatively great distance into the body member 1 and, thereby, serve as mechanical reinforcing means throughout a considerable portion of the length of the insulator. Because the rupturing strength of insulating materials is greater than that -of air, a the outside of the insulator rather than through it and this fact is taken advantage of in the shaping and proportioning of the parts. a

dielectric breakdown will occur over That is, the portions 6 and 7 may extend toward each other a certain greater distance than the flanges 4 and 5 may so extend and still maintain dielectric breakdown outside rather than through the insulator. This greater length` of the portions 6 and 7 provides the portionsV with surface areas that not only effect greater mechanical bond be tween the metal and insulating parts but also, in combination with the transverse inner walls of the parts 6 and 7 and the rounded inner endperimeters of these parts effect wider'- distribution of the electrostatic stresses between the terminals and prevent concentration of these stresses.

Being single integral members of relatively thin metal having a substantially uniform thickness throughout, the members v2 and 3 are readily adapted to an economical pressing manufacturing operation. Also, by reason of their light weight, the expansion forces are reduced to render damage to the insulator less likely and a more economical structure of ready manipulation and shipping to be obtained.

The hollow structure of the portions 6 and 7 is particularly desirable in preventing damage y expansion but, by reason of the closed ends thereof, these portions serve to direct the electrostatic stresses the same as solid members. i

The flanges 4 and 5 also serve as means for protecting the ends of the insulating body member 1 at positions where the latter is most likely to be damaged during the mounting of heavy conductors and being tubular and integral with the remainder of the members 2 and 3, serve to strengthen the latter.

The members 2 and 3 substantially conform to the ends of the body member but are .slightly spaced therefrom to admit bodies of cement 8, or other suitable material, such a Babbitt metal, therebetween to hold the members 2 and 3 in position.

In Fig. 2 the body member 1 is preferably formed hollow throughout its length to receive a body of rubber compound 9 or other suitable insulating filler material that may be admitted to the insulator through an opening 10 in the end member 2 after the members filler material cools and contracts some of the excess thereof in the portion 6 will be l drawn into the insulator to completely fill the latter. When in service, the opening l() may act as a breather for the material 9 or means wherebythe latter may be extruded from ,the insulator in response to rises in temperature and be drawn into the insulator when the temperature again falls.

llllhile I have shown and described particular forms of my invention, changes may be effected therein without departing from the spirit and scope thereof, as set forth in the appended claims.

l claim as my invention:

l. An insulator unit comprising a dielectric column and metal terminal members therefor, one of which is constructed as a single integral piece of substantially uniformlythick sheet-like metal embodying a central mechanically-anchoring and electrostaticstress-distributing portion of cup-shape eX- tending into the column having a transverse inner-end wall and a rounded inner-end perimeter, an annular end supporting-base portion projecting laterally from the mouth of the cup and an annular flange projecting from said supporting-base portion toward the other terminal member a distance less 'than the inner end of the cup for mechanically protecting the end of the dielectric column, assisting in controlling the electrostatic field of the insulator and constituting attaching means.

2. An insulator unit comprising a dielectric column and a metal terminal member at each end thereof, each embodying a central portion of substantially cup-shape eX- tending into the column having a transverse inner-end wall and a rounded inner-end perimeter, an annular intermediate portion projecting laterally from the mouth of the cup and a flange projecting from said intermediate portion toward the other terminal a distance less than the inner end of the cup, the

cup of the lower terminal member extending into the column a greater distance than the cup of the upper terminal member.

3. An insulator unit comprising a dielectric column and a metal terminal member at each end thereof, each embodying a central portion of substantially cup-shape extending into the column having a transverse innerend wall and a rounded inner-end perimeter, an annular intermediate portion projecting laterally from the mouth of the cup and a flange projecting from said intermediate portion toward the other terminal a distance less than the inner end of the cup, a cup of the lower terminal member being of greater diameter than the cup of the upper terminal member.

4. An insulator comprising ceramic dielectric and metallic terminal elements providing a substantially entirely-enclosed space, and a dielectric filler material capable of flowing aeeaeoe and having a dielectric strength greater than air substantially entirely filling said space, one of said elements having a rela-tively small breathing opening for said filler material.

5. An insulator comprising ceramic dielectric and metallic terminal elements providing a` substantially entirely-enclosed space, and a dielectric filler material capable of flowing and having a dielectric strength greater than air substantially entirely filling said space, one of said elements having a relatively small breathing opening for said filler material and a portion adjacent to the exit of the opening for receiving filler material and permitting it to flow into theopenmg.

6. The combination with a hollow cylindrical refractory insulating member and a body of insulating filler material capable of flowing disposed therein intermediate the ends thereof to provide separated axially extending end openings therefor, of a single integral metal member of relatively thin, substantially uniformly thick sheet formation at each end of said insulating member having an outer longitudinal flange surrounding the end of the insulating memberfor a definite distance therealong toward the corresponding flange of the other metal member, an annular portion covering the transverse end surface of the insulating member between the Opening and the outer perimeter thereof and a portion of substantially cup-shape projecting into the adjacent end opening of the insulator, one of said metal members having a relatively small opening through the end wall of the cup to permit portions of said filler material to move in said opening in vresponse to temperature changes, the inner ends of said portions of cup-shape being spaced closer to each other than the adjacent inner edges of the outer flanges in accordance with the difference between the dielectric strength of said body of insulating filler material and the dielectric strength of the surrounding medium between the outer flanges.

7. The combination with a tubular insulating member and ay body of insulating material capable of flowing disposed therein to provide separated end openings therefor, of a metal member at each end thereof having a fiange outside the tube extending toward the other flange and a cup in the tube connected at its open end to its corresponding end flange, one of said cups having an openingpermitting portions of said body to move therein in response to temperature changes "and the inner ends of the cups being spaced closer to each other than the adjacent edges of the flanges in accordance with the difference between the dielectric strength of said body and the dielectric strength ofthe medium between the flanges.

8. The combination with a tubular insulating member and a. body of insulating material cap-able of flowing disposed therein to therein in response to temperature changes provide separated end openings therefor, of a and the inner ends of the cups being spaced 10 metal member at each end thereof having a 'closer to each other than the adjacent edges ange outside the tube extending toward the of the anges.

other ange and a cup in the tube connected In testimony whereof, I have hereunto subat its open end to its corresponding end flange, scribed my name this 13th day of March, the -upper of said cups having an openingj1920.

permitting portions of said body to move vCI-IRISTIAN AALBORG. l 

